Implement arbiter

backend/backend/arbiter.py

@@ -0,0 +1,191 @@
+import asyncio
+from datetime import datetime, timedelta
+from dataclasses import dataclass
+import random
+from socket import socket
+from typing import Callable, Awaitable
+
+from fastapi import WebSocket, WebSocketDisconnect
+
+from .settings import settings
+from .input import EMPTY_INPUT, Button, Input
+from .pag import input as pag_input
+
+InputGetter = Callable[[None], Awaitable[list[Input]]]
+OutputSetter = Callable[[Input], None]
+ModeFunction = Callable[[InputGetter, OutputSetter], None]
+
+
+@dataclass
+class GameMode:
+    name: str
+    mode_function: ModeFunction
+    allow_multitouch: bool
+
+
+@dataclass
+class State:
+    mode: str
+    allowMultitouch: bool | None
+
+    nextMode: str
+    timeUntilNextMode: float
+    votes: dict[Button, int]
+
+    # playerIdle: bool  # set individually for each client
+
+
+class ClientState:
+    def __init__(self):
+        self.current_input = EMPTY_INPUT
+        self.inactivity_task = None
+        self.is_active = False
+
+    def on_input(self, input: Input):
+        self.current_input = input
+        self.is_active = True
+        if self.inactivity_task:
+            self.inactivity_task.cancel()
+        self.inactivity_task = asyncio.create_task(self.deactivator())
+
+    async def deactivator(self):
+        await asyncio.sleep(settings.CLIENT_IDLE_TIMEOUT)
+        self.is_active = False
+        self.inactivity_task = None
+
+
+class Arbiter:
+    def __init__(self):
+        self.modes: list[GameMode] = []
+        self.state = State("", False, "", 0, dict())
+        self.current_mode = None
+        self.current_mode_task = None
+        self.modeswitch_time = None
+        self.clients: dict[WebSocket, ClientState] = dict()
+
+    def mode(self, name: str, allow_multitouch: bool = True):
+        def inner(f: ModeFunction):
+            self.modes.append(GameMode(name, f, allow_multitouch))
+
+        return inner
+
+    async def handle_socket(self, socket: WebSocket):
+        self.clients[socket] = ClientState()
+        while True:
+            try:
+                data = await socket.receive_json()
+                self.clients[socket].on_input(data)
+            except WebSocketDisconnect:
+                break
+        del self.clients[socket]
+
+    async def get_input(self):
+
+        # filter players
+        allowed_multitouch = 1 if self.current_mode.allow_multitouch else 10
+        active_player_inputs = [
+            client.current_input
+            for client in self.clients.values()
+            if client.is_active
+            and sum(client.current_input.values()) <= allowed_multitouch
+        ]
+
+        # update vote histogram
+        self.state.votes = {
+            button: sum(input[button] for input in active_player_inputs)
+            for button in Button
+        }
+
+        return active_player_inputs
+
+    def set_output(self, output: Input):
+        pag_input.set(output)
+
+    def update_next_mode(self):
+        choices = [mode for mode in self.modes if mode != self.current_mode]
+        if choices:
+            self.next_mode = random.choice(choices)
+        else:
+            self.next_mode = self.current_mode
+        self.state.nextMode = self.next_mode.name
+
+    async def main_loop(self):
+        # current_mode is None / ""
+        self.update_next_mode()
+
+        while True:
+            # switch modes
+            self.current_mode = self.next_mode
+            self.state.mode = self.current_mode.name
+            self.update_next_mode()
+            self.modeswitch_time = datetime.now() + timedelta(
+                seconds=settings.ARBITER_MODE_SWITCH_CYCLE
+            )
+
+            if self.current_mode_task:
+                self.current_mode_task.cancel()
+            self.current_mode_task = asyncio.create_task(
+                self.current_mode.mode_function(self.get_input, self.set_output)
+            )
+
+            # send updates until next mode switch
+            while (now := datetime.now()) < self.modeswitch_time:
+                self.state.timeUntilNextMode = (
+                    self.modeswitch_time - now
+                ).total_seconds()
+
+                await asyncio.gather(
+                    asyncio.sleep(settings.ARBITER_TICK_CYCLE),
+                    *[
+                        socket.send_json(
+                            {
+                                **self.state.__dict__,
+                                "playerIdle": not self.clients[socket].is_active,
+                            }
+                        )
+                        for socket in self.clients
+                    ],
+                    return_exceptions=True,
+                )
+
+
+arbiter = Arbiter()
+
+
+@arbiter.mode("democracy", allow_multitouch=False)
+async def _(get_input: InputGetter, set_output: OutputSetter):
+    while True:
+        await asyncio.sleep(settings.DEMOCRACY_VOTE_CYCLE)
+
+        vote = {button: 0 for button in Button}
+        vote["none"] = 0
+
+        inputs: list[Input] = await get_input()
+
+        if not inputs:
+            set_output(EMPTY_INPUT)
+            continue
+
+        for input in inputs:
+            # since multitouch is not allowed, we can assume that
+            # at most one entry is true
+            for button in Button:
+                if input[button]:
+                    vote[button] += 1
+                    break
+            else:
+                # cursed python syntax
+                vote["none"] += 1
+
+        max_choice = None
+        max_votes = -1
+        for (choice, votes) in vote.items():
+            if votes > max_votes:
+                max_votes = votes
+                max_choice = choice
+
+        output = EMPTY_INPUT
+        if max_choice != "none":
+            output[max_choice] = True
+
+        set_output(output)

backend/backend/input.py

@@ -2,6 +2,7 @@ from enum import Enum
 from dataclasses import dataclass
 from typing import Literal
 
+
 class Button(str, Enum):
     UP = "up"
     DOWN = "down"
@@ -17,6 +18,8 @@ class Button(str, Enum):
 
 Input = dict[Button, bool]
 
+EMPTY_INPUT = {button: False for button in Button}
+
 KEYMAP = {
     Button.UP: "up",
     Button.DOWN: "down",
@@ -30,6 +33,7 @@ KEYMAP = {
     Button.SELECT: "backspace",
 }
 
+
 @dataclass
 class Event:
     button: Button

backend/backend/pag.py

@@ -1,9 +1,7 @@
 import pyautogui
 from threading import Thread, Event
 
-from .input import KEYMAP, Input, Button, Event as InputEvent
-
-EMPTY_INPUT = {button: False for button in Button}
+from .input import KEYMAP, Input, EMPTY_INPUT, Button, Event as InputEvent
 
 
 class InputHandler:

backend/backend/settings.py

@@ -0,0 +1,13 @@
+from pydantic import BaseSettings
+
+
+class Settings(BaseSettings):
+    CLIENT_IDLE_TIMEOUT: float = 10
+
+    ARBITER_TICK_CYCLE: float = 0.1
+    ARBITER_MODE_SWITCH_CYCLE: float = 10
+
+    DEMOCRACY_VOTE_CYCLE: float = 0.25
+
+
+settings = Settings()

backend/backend/web.py

@@ -6,31 +6,25 @@ from fastapi.responses import FileResponse
 
 from .pag import input as pag_input
 from .input import Button
+from .arbiter import arbiter
 
 app = FastAPI()
 
 backend = FastAPI()
 
 
+@app.on_event("startup")
+async def on_startup():
+    print("startup hook")
+    asyncio.get_running_loop().create_task(arbiter.main_loop())
+
+
 @backend.websocket("/client")
 async def client_handler(socket: WebSocket):
-    print("WS opened")
+    print("[web] WS opened")
     await socket.accept()
-
-    input = {button: False for button in Button}
-
-    while True:
-        try:
-            data = await socket.receive_json()
-            print(f"WS data: {data!r}")
-            button = data["button"]
-            pag_input.set({**input, button: True})
-            await asyncio.sleep(0.1)
-            pag_input.set({**input, button: False})
-        except WebSocketDisconnect:
-            break
-
-    print("WS closed")
+    await arbiter.handle_socket(socket)
+    print("[web] WS closed")
 
 
 frontend = FastAPI()